Adjustable pitch dipper means



Nov. 23, 1965 T. LEARMONT ADJUSTABLE PITCH DIPPER MEANS 4 Sheets-Sheet 1Filed Jan 14, 1965 INVENTOR. TOM LEARMONT ATTORNEY NOV. 23, 1965LEARMQNT 3,219,213

ADJUSTABLE PITCH DIPPER MEANS Filed Jan. 14, 1963 4 Sheets-Sheet 2 FIG.3

m @Ej i 55 FIG. 4

INVENTOR. TOM LEARMONT BY @MZ/Aw ATTORNEY Nov. 23, 1965 T. LEARMONTADJUSTABLE PITCH DIPPER MEANS 4 Sheets-Sheet 3 Filed Jan. 14, 1965 FIG.5

FIG. 6

INVENTOR. TOM LEARMONT ATTORNEY Nov. 23, 1965 LEARMONT 3,219,213

ADJUSTABLE PITCH DIPPER MEANS Filed Jan. 14, 1963 4 Sheets-Sheet 4INVENTOR. TOM LEARMONT ATTORNEY United States Patent ()fiice 3,219,213Patented Nov. 23, 1965 3,219,213 ADJUSTABLE PITCH DIPPER MEANS TornLearmont, 8600 Glencoe Circle, Wauwatosa, Wis. Filed Jan. 14, 1963, Ser.No. 251,287 9 Claims. (Cl. 214-137) This invention relates to excavatorsand more particularly to power shovels having a dipper pivotally mountedon a dipper handle wherein said dipper is adjustably pivoted relative tosaid dipper handle.

Power shovels are used in the mining of coal, ore and the like. Thedipper of such power shovels is filled or loaded by a forward thrust orcrowding action of the dipper handle. The loaded dipper is hoisted overa truck, pile or the like where the dipper is emptied by allowing thedoor of the dipper to swing open.

In the design of dippers and the attachment thereof to dipper handles,consideration must be given to both the digging and the dumpingefiiciency of the dippers. If the dipper is designed to be afiixed tothe dipper handle without any provision for pivoting of the dipper withrespect to the handle, it is possible that digging efiiciency will beobtained during the digging cycle of the power shovel, but the dipperwill not be positioned for efficient discharge at the dumping portion ofthe cycle. For efiicient dumping of the dipper, the door should beallowed to swing clear to allow the loaded material to drop freely fromthe dipper, and the walls of the dipper should be substantially verticalso that the loaded material will drop freely from the dipper walls. As apower shovel is often required to work in a variety of locations, theshovel dipper does not always dump from the same distance from theground. Therefore if the dipper is afiixed in a constant angularrelation to the dipper handle, the walls of the dipper will not bevertical at a variety of dipper dump positions.

If, on the other hand, the dipper is designed to dump cleanly and thedipper is returned to digging position it is possible that the heel ofthe dipper will strike the ground before the dipper teeth engage theground thereby causing a skidding of the dipper over the ground. Suchskidding causes dipper heel wear.

If, to avoid heel wear, the dipper is affixed to the handle at anefiicient digging angle, the dipper is ordinarily in a tilted positionat the dumping portion of the cycle which results in ineflicientdischarge of material from the dipper and consequently the overallefliciency of the power shovel operation is reduced.

It is, therefore, advantageous to provide a dipper which is pivotallyattached or hinged to the dipper handle whereby the pitch or angularrelation of the dipper to the handle may be varied during the operationof the shovel. In this way, the dipper can have the desired angularrelationship to the dipper handle for efficient digging, and by varyingthe pitch or angular relationship of the dipper, the dipper can bepositioned for efficient discharge of the loaded material from thedipper.

Further, if the pitch of the dipper can be varied as the dipper teethemerge from the ground, for example, by tilting so that the upper partof the dipper wall and teeth move toward the power shovel, the dippercan carry more material to the dumping portion of the cycle. Tilting ofthe dipper allows the loaded material to fall back into the dipperrather than spill outwardly past the dipper teeth. With proper tilting,less material is spilled as the dipper handle and dipper are swung to adischarge location. Such spillage from the dipper often results instrewn rocks over an area where rubber tired dump trucks travel therebycausing a hazardous driving condition, and a condition that results inexcessive wear of the truck tires.

Thus, by providing a means for tilting the dipper, particularly a meanscontrollable by a power shovel operator, the dipper may be tilted to thedesired angle with respect to the dipper handle for the most efiicientdigging and dumping. Such tilting control improves the overallefiiciency of the power shovel operation.

One embodiment of the invention provides a tilting means for the dipperwhereby the dipper is tilted for efiicient discharge, and the dipper isrepositioned to the proper tilt for efiicient digging by forcing thedipper against the ground at the beginning of the digging cycle.

In a second embodiment, a tilting means is provided for tilting thedipper for efficient discharge therefrom and wherein retraction of thedipper handle actuates a means for returning the dipper to the desiredtilt for eflicient digging.

The third embodiment of the invention provides a mechanical linkagemeans for tilting the dipper to an efircient discharge position when thedipper door is opened, and wherein closure of the door repositi-ons thedipper to digging position.

It is therefore an object of this invention to provide a means fortilting a dipper with respect to a dipper handle to provide forefiicient discharge of material therefrom, and wherein said dipper isrepositionable during the initiation of dipper digging action.

It is another object of this invention to provide a means for tiltingthe dipper while the dipper is returned to the digging portion of powershovel operation.

It is an object of this invention provide a tilting means for a dipperto avoid excessive heel wear on the dipper.

It is a further object of this invention to provide a tilting meansunder control of an operator for positioning a dipper in the dumpportion of the cycle to allow an efiicient discharge of material fromsaid dipper.

It is an object of this invention to provide dipper tilting means forimproving the loading of the dipper and for preventing spillage fromsaid dipper in the loaded condition.

It is another object of this invention to provide means for tilting thedipper when the dipper door is opened, and wherein movement of saiddipper and the dipper handle toward digging position causes said door toclose thereby returning said dipper to a predetermined digging tiltposition with respect to said dipper handle.

It is a further object of the invention to provide a tilting meanswherein said dipper is urged in a digging tilt position and wherein saiddipper is tiltable to a discharge tilt position by actuation of saidtilting means wherein pull on a hoist rope and a load in said dipper aidin positioning the dipper to discharge tilt position.

These and other objects of this invention may be found in theaccompanying specification, claims and drawings, of which:

FIGURE 1 is a side elevation of a power shovel having tilting means fora dipper;

FIGURE 2 is an enlarged elevation of the dipper of FIGURE 1;

FIGURE 3 is an enlarged elevation of the tilting means of the dipper ofFIGURE 1;

FIGURE 4 is a schematic diagram of the fluid circuit of the tiltingmeans of FIGURE 3;

FIGURE 5 is an elevation view of a second embodiment of a tilting meansfor the dipper of FIGURE 2;

' FIGURE 6 is a schematic diagram of the fluid circuit of the tiltingmeans of FIGURE 5;

FIGURE 7 is an elevation of a third embodiment of the invention; and I vFIGURE 8 is an elevation view of the dipper tilted by the tilting meansof FIGURE 7.

Referring now to FIGURE 1, a power shovel 11 is shown having a frame 12rotatably mounted on a crawler means 13. A'boom 14 is pivotally attachedto the frame 12 as at pivot 15. The frame also carries a boom hoistwinch 16, a dipper hoist winch 17, and a dipper thrusting winch 18.

Winch 16 manipulates boom suspension cables 19 to raise and lower boom14. Winch 17 manipulates hoist ropes 20 to raise and lower dipper 21.The hoist ropes pass over boom point sheaves 43 to a pair of laterallyspaced lugs'22 carried by the dipper 21.

The dipper 21 is hingeably mounted at pivot or hinge 40 on the outer endof the dipper handle 23. Handle 23 is slideably carried by a saddleblock 24 which is pivotally carried on boom 14. Winch 18 manipulatesthrust rope 25, attached to the rear end of dipper handle 23, andretracting rope 26, attached to the front end of handle '23; both ofthese ropes 25 and 26 are manipulated by Winch 18 and attached to handle23 to provide for a thrust and retract movement of the dipper handle 23.1 The dipper 21 is shown in discharge position over a dump truck 10. Thedipper is discharged by the opening of dipper door 27. When the forwarddipper wall 28 is inclined in a forwardly direction there is apossibility of retention of some of the material in the dipper. Indotted lines, a position of the dipper 21 is shown wherein wall 28 issubstantially vertical, which allows an efficient discharge of materialfrom the dipper 21 when the door 27 is opened.

A fluid pressure means'30 is shown between the handle 23 and dipper 21for controlling the pivoting of the dipper about pivot 40. The tiltingmeans 30 consists primarily of a fluid pressure cylinder 31 (FIGURE 2)having a retractible piston 32 wherein fluid pressure in the cylinderacts on the piston to maintain the piston in'retracted position and thedipper 21 in digging position as disclosed by the solid line dipper 21of FIGURE 1. The dipper is positionable about pivot 40 to the dischargeposition shown, for example, in broken lines of FIG- URE l.

After the dipper discharges into the truck 10, the dipper handle 23jisretracted by winch 18 and rope 26 and the dipper 21 is then loweredtoward digging position by'exten'sion of the handle. When the dipperteeth 42 are thrust into the ground, the force on the dipper pivotsdipper 21 about pivot 40 to return the dipper to digging positionwherein the dipper is maintained at the desired tiltfor' digging bymeans -During digging .when the teeth 42 of the dipper 21 emerge fromthe ground, the fluid pressure tilting means 30 may 'be actuated toallow partial tilt of the dipper toward its discharge position. Inthis'way, the dipper 'wall 28 approaches a vertical position'and the newtilted position of the dipper aids in retaining a greater quantity ,ofmaterial in the dipper than would have been carried by the dipper if notilting had occurred. As the dipper in FIGURE 4.

driving conditions and the spilled rock or debris is likely to causeexcessive truck tire wear.

In FIGURE 2 fluid pressure means 30 is pivotally attached to dipperhandle 23 as at pivot block 35 and to dipper 21 at pivotal hinge means29. The dipper is mounted for pivotal movement at hinge or pivot 40 onhandle 23. Fluid pressure in cylinder 31 acts on retracted piston 32 tomaintain the dipper 21 in digging position shown in solid lines, whichis the position of the dipper in relation to the handle when the dipperis thrust or crowded into engagement with the ground.

The position of the dipper 21 indicated by broken lines in FIGURE 2 isthe tilted position of the dipper for discharging material therefrom.The dipper discharge tilt position is obtained by the relieving orreducing the fluid pressure acting on piston 32 to'allow the piston tomove outwardly of the cylinder 31 as viewed in the drawings. The tiltedposition of the dipper 21 delineated by the broken lines results fromthe action of hoist rope .20 acting at moment M from pivot 40 and thetendency of the loaded dipper to move in a counterclockwise positionabout pivot 32 when the pressure on piston 32' is relieved. Duringtilting the'forward wall 28 of the dipper reaches a nearly verticalposition. The door 27 is opened by disengaging latch means 41 by a ropemeans (not shown). -Material in the dipper is thereby allowed to dropfreely from the dipper walls.

To return the dipper 21 to the digging position of FIG- URE 2 afterdischarge of material, the dipper teeth 42 engage the ground as thedipper handle 23 is extended downwardly. The force on the teeth causesthe dipper to pivot clockwise about pivot 40 to force piston 32 inwardlyof the cylinder 31. The action of the fluid in fluid pressure means 30during repositioning of the dipper is described in detail hereinbelow.

Reference is now made to FIGURES 3 and 4 wherein the fluid pressurecircuit of fluid pressure means 30 is described. The-cylinder 31 isprovided with a retractible piston-32 acted upon by a fluid pressure tomaintain the piston and connected dipper 21 ina clockwise directionabout pivot 40. A piston pivot 33 on piston 32 is pivotally attached tohinge29 of dipper door 27. 'A cylinder pivot 34 carried by cylinder 31is pivotally attached to pivot lug 35 on the dipper handle 23.

To tilt the dipper in a counterclockwise direction about pivot 40 to adipper discharge position, it is necessary to release the fluid pressureacting on piston 32. When the fluid pressure on piston 32 is releaseda'hoisting force applied by the hoist ropes 20 and the loaded dippercauses the dipper to discharge or dump position.

Further detail of the fluid pressure circuit 50 is shown Initiallycircuit 50 is charged with fluid at filler valve 53. In the disclosedembodiment hydraulic fluid is pumped into fluid pressure conduits 39. Ataccumulators 37, suflicient air is supplied through valves 54 to providea cushion of air in the accumulators. The pistons 32 are in their inwardor retracted position as "shown in FIGURE 4 during the charging of thecircuit.

With the fluid pressure maintaining the pistons 32 in their retractedposition, and with the remainder of the conduits filled with fluid,thecircuit is considered charged to maintain the pistons in thepositions shown in FIGURE 4. With cylinder 31 connected to the dipperhandle (FIG- URE 3) and piston 32 connected to the dipper 21 (FIG- URE3), the fluid pressure means 30 maintainsjthe dipperin digging tiltposition (FIGURE 3).

1 To tilt the dipper towarddischarge or dump position,

ropes 20 (FIGURE 2) pulling on dipper 21 at'a moment ,arm M to pivot thedipper counterclockwise about pivot 40, the piston 32 is moved outwardlyof the cylinder 31 until the dipper 21 reaches discharge tilt position.A load in the dipper also tends to pivot the dipper counterclockwiseabout pivot 40.

To return the dipper to digging tilt position, the dipper is moved bythe dipper handle 23 to engage the ground. The force occasioned by theextension of handle 23 pivots dipper 21 clockwise about pivot 40 and thefluid is forced from cylinder port 3112 by piston 32 through check valve52 to port 31a to restore fluid pressure against piston 32 to maintaindipper 21 in digging tilt position.

If during digging an excessive force on the dipper causes an increase influid pressure in cylinder 31 beyond a predetermined amount, reliefvalve 56 opens to relieve the build-up of fluid pressure within cylinder31 and conduits 39. When the pressure is reduced, valve 56 closes.

Thus the first embodiment of the invention has been described wherein afluid pressure means 30 is provided to maintain the dipper in apredetermined tilted position relative to said dipper handle 23. In theembodiment disclosed, the fluid pressure maintains the dipper in diggingtilt position, and release of the fluid pressure allows the dipper to betilted to dipper discharge tilt position relative to said handle. As thefluid pressure circuit is initially charged with fluid pressure tomaintain the dipper in the digging tilt position, no further fluidpressure producing means is required to maintain suflicient pressure,but rather the fluid pressure circuit as described provides for releaseand restoration of fluid pressure in fluid pressure means 30.

Referring now to FIGURE 5 wherein a second embodiment of the inventionis shown with a dipper 21 pivotally mounted on dipper handle 23. Againfluid pressure acting on the piston means 32 maintains the dipper indigging tilt position, and the release of fluid pressure in cylinder 31allows the dipper to pivot counterclockwise about pivot 40 to dumping ordischarge tilt position. In the embodiment shown in FIGURE 5, a fluidpressure ram means 60 is mounted on the dipper handle 23, adjacentsaddle block 24. A ram piston 61 extends from ram means 60 wherein oneend of the piston 61 is adapted to strike the saddle block when thedipper handle is retracted, as for example, after discharge of materialfrom the dipper. As retract rope 26 (FIGURE 1) retracts handle 23, rampiston 61 is brought into contact with saddle block 24 and the handleretraction forces the piston 61 to retract position to force fluid fromthe cylinder 62 into fluid pressure conduit 65. The fluid in conduit 65is communicated with port 31a of cylinder 31 to supply a fluid pressureto force pistons 32 to retract position thereby pivoting dipper 21 todigging tilt position. In this embodiment, it is not necessary for thedipper to strike the ground during the initiation of the digging cycle,as the dipper is repositioned to digging tilt position by the fluidpressure action of the ram piston 61 striking the saddle block duringretraction of the dipper handle as described hereinabove.

In FIGURE 6, a schematic diagram of the fluid pressure circuit for theram means 60 and cylinders 31 is shown. The cylinders 31 with fluidpressure acting on pistons 32 maintain the dipper in digging tiltposition. When solenoid 36 is energized by an operator to open valve 51,fluid flows from cylinder port 31a to release the pressure acting onpistons 32. The dipper is then free to be tilted about the pivot 40 byhoisting action of hoist ropes 20 until the dipper wall 28 (FIGURE 2) issubstantially vertical.

The load in the dipper also acts to assist the tilting of the dippercounterclockwise about pivot 40 when pressure is relieved from cylinder31. The fluid is allowed to flow to ports 31b and to accumulators 37.When the dipper is in discharge tilt position, the dipper door 27 isopened by unlatching latch 41 (FIGURE 2) by a means not shown but Wellknown in the power shovel art.

For returning the dipper to the digging tilt position,'the dipper handle23 is retracted to cause the ram piston 61 to strike the saddle block 24to force fluid into conduit 65 to apply a fluid pressure to the pistons32 to position the dipper 21 into digging tilt position as hereinabovedescribed.

Thus a fluid pressure means 30 is provided wherein the dipper ismaintained in a digging tilt position. When solenoid 36 is energized thedipper is positionable to discharge tilt position by hoist ropes 20. Theram piston 61 in striking the saddle block 24 upon retraction of thehandle 23 produces sufiicient fluid pressure to return the dipper 21 todigging tilt position.

In FIGURES 7 and 8 a third embodiment of the invention is shown fortilting the dipper for effieient discharge of material therefrom. Thedipper 21 is pivotally attached to handle 23 as at pivot 40. A pivot lug71 is carried by the dipper handle 23 for pivotal attachment of a link70. The dipper door 27 is hingeably attached to dipper 21 at hinge orpivot 29, and is latched for closure by a door latch 41, which may beopened and closed by suitable means not shown. Adjacent hinge 29, linkis pivotally attached at pivot 72. With the dipper 21 in the positionshown in FIGURE 7, the dipper is in the digging tilt position. Thedigging position of the dipper is maintained as long as the door 27remains closed.

When the dipper 21 has completed the digging portion of the cycle andthe dipper is moved to a location for dumping or discharge, theembodiment of the invention of FIGURES 7 and 8 provides for the tiltingof the dipper relative to the handle so that the dipper wall 28 is in asubstantially vertical position. The vertical position of the dipperwall 28 allows material in the dipper to fall freely without clinging tothe walls.

Referring specifically to FIGURE 8, the dipper door 27 is shown in openposition. As the door swings open upon unlatching of latch means 41, theweight of the door and a material acting thereon causes the door toswing clockwise about pivot 29. Simultaneously, as the dipper dooropens, the door moves pivot 72 upwardly as viewed in the drawings andthus the entire dipper is pivoted counterclockwise about pivot 40 to aposition wherein the forward dipper wall 28 becomes substantiallyvertical.

In the embodiment disclosed in FIGURES 7 and 8, the tilting of thedipper occurs only when the dipper door is opened or closed. When thedoor is opened, the dipper, through linkage 70 and pivots 29 and 72, ismoved to discharge tilt position as shown in FIGURE 8. To return thedipper to digging tilt position shown in FIGURE 7, the door of thedipper is closed by the weight of the door as the dipper handle swingstoward digging position. As the door is closed, link 70 coacting withpivots 29 and 72 causes the dipper to pivot clockwise about pivot 40until the digging tilt position is reached. Latch 41 and link 70maintain the door closed and also maintain the dipper in digging tiltposition.

Thus three embodiments of the invention have been described wherein apivotally mounted dipper is provided with a tilting means. Two of theembodiments not only provide for tilting the dipper to the discharge ordumping position but also provide a means to permit tilting of thedipper as the dipper teeth emerge from the ground in the digging portionof the cycle to allow the dipper to fill more completely and to reducethe amount of spillage from the dipper when the dipper is carried to thedump location.

Also one of the embodiments rely on dipper impact against the ground toreposition the dipper for digging, while another embodiment is providedwith an additional means for repositioning the dipper to dig positionprior to the engagement of the dipper teeth with the ground, and thethird embodiment repositions the dipper upon closure of the door.

'Having now described and illustrated three forms of the presentinvention, it is to be understood that the invention is not to belimited .to the specific form or arrangement of parts herein describedand shown or specifically covered by the claims.

What is claimed is:

1. Inan excavator having a boom, a saddle block .pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, meansfor retracting and thrusting said dipper handle, and a dipper pivotallymounted on said dipper handle, the combination of: hoist means connectedto the dipper at a point forwardly spaced from the dipper pivot forraising and lowering the dipper and dipper handle and for tilting thedipper in an upward direction about the dipper pivot when said dipper isfree to tilt about its pivot; and fluid pressure means, including acylinder and a retractible piston, connected to said dipper handle andsaid dipper, a fluid pressure circuit for maintaining fluid pressure insaid cylinder to maintain said piston in a retracted position, and fluidpressure release means in said fluid pressure circuit for releasingfluid pressure in said cylinder to allow said piston to move fromretract position, said dipper being tiltable to a dipper dischargeposition upon release of fluid pressure and upon application of ahoisting force'on said dipper by said hoist means, and said dipper beingtiltable in a downward direction about said dipper pivot to a dipperdigging position by thrusting said handle and dipper into groundengagement to force said piston to retract position.

' 2.'The combination of claim 1 wherein fluid pressure is restored tosaid fluid pressure means as said piston is moved to retract position byground engagement of said dipper tilting said dipper in clockwisedirection about said dipper pivot.

3. In an excavator having a boom, a saddle block pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, meansfor retracting and thrusting said dipper handle, and a dipper pivotallymounted on said dipper handle, the combination of:

locking means connected between said dipper handle and said dipper formaintaining said dipper in a first tilt position; release means forunlocking said locking means to free said dipper to move to a secondtilt position; and means connected to said dipper at a point forwardlyspaced from the dipper pivot for raising and lowering said dipper anddipper handle when said locking means is engaged and for tilting saiddipper upwardly about the dipper pivot to said second tilt position whensaid locking means is unlocked by said release means.

4. In an excavator having a boom, a saddle block pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, and adipper pivotally mounted on said dipper handle, the combination of:

'hoist means connected to the dipper for raising and lowering saiddipper'and dipper handle and for tilting said dipper upwardly about thedipper pivot when said dipper is free to tilt, fluid pressure meansconnected between said dipper and said dipper handle and having a.firstfluid pressure for maintaining said dipper in a first tilted position;and a fluid pressure release means for said fluid pressure meansforreleasing said first fluid pressure to allow said dipper to tilt to asecond tilted ,position, said hoist means adapted to tilt said dipperreleasing .said first fluid pressure to allow said dipper to tilt tosaid first tilt position.

7. In an excavator having a boom, a saddle block pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, meansfor retracting and thrusting said dipper handle relative to said saddleblock, and a dipper pivotally mounted on said dipper handle, thecombination of: hoist means connected to the dipper at a point forwardlyspaced from the dipper pivot for raising and lowering the dipper anddipper handle and for tilting the dipper in an upwardly direction aboutthe dipper pivot when said dipper is free to tilt about its pivot; firstfluid pressure means, including a cylinder and a retractible piston,connected between said dipper handle and said dipper, a fluid pressurecircuit for maintaining fluid pressure in said cylinder to maintain saidpiston in a retracted position, and fluid pressure release means in saidfluid pressure circuit for releasing fluid pressure in said cylinder toallow said piston to move from retract position to allow said dipper totilt about its pivot; fluid pressure ram means carried by said dipperhandle and moveable therewith, said ram means adapted to be actuatedduring retraction of said dipper handle, said dipper being tiltable to adischarge position upon release of fluid pressure by said fluid pressurerelease means and upon application of a hoisting force on said dipper bysaid hoist means; and second fluid pressure means responsive to theactuation of said ram means for producing a fluid pressure forretracting said piston to tilt said dipper from discharge position todigging position.

8. In an excavator having a boom, a saddle block pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, meansfor retracting and thrusting said dipper handle relative to said saddleblock, and a dipper pivotally mounted on said dipper handle, thecombination of: hoist means connected to the dipper at a point forwardlyspaced from the dipper pivot for raising and lowering the dipper anddipper handle and for tilting the dipper in an upward direction aboutthe dipper pivot when said dipper is free to tilt about its pivot; fluidpressure means, including a cylinder and a retractible piston, connectedbetween said dipper handle and said dipper, a fluid pressure circuit formaintaining fluid pressure in said cylinder to maintain said piston in aretracted position, and fluid pressure release means in said fluidpressure circuit for releasing fluid pressure in said cylinder to allowsaid piston to move from retract position to allow said dipper to tiltabout its pivot; and fluid pressure ram means carried by said dipperhandle and moveable therewith, said fluid pressure ram means including aram piston engaging said saddle block when said dipper handle isretracted by dipper handle retract. means, a fluid pressure produced bysaid ram means upon predetermined displacement of said ram piston bysaid saddle block, said fluid pressure means being responsive to saidfluid pressure produced by said ram means to retract said piston of'saidfluid pressure means, said dipper being tiltable to a discharge positionupon release of fluid pressure by said fluid pressure release meansand'upon application of a hoisting force on said dipper by said hoistmeans, and said dipper being tilted to digging. position in response tosaid fluid pressure produced by said displacement of said ramvpist-on.

9.. Man excavator having a boom, a saddle block pivotally mounted onsaid boom, a dipper handle slideably carried by said saddle block, meansfor retracting and thrusting said dipper handle relative to said saddleblock, and a dipper pivotally mounted on said dipper handle, thecombination of: means connected to the dipper at a point forwardlyspacedfrom the dipper pivot for raising and lowering the dipper anddipper handle and for tilting thedipper in an upward direction about 910 the dipper pivot when said dipper is free to tilt about ReferencesCited by the Examiner its pivot; locking means connecting said dipperand said UNITED STATES PATENTS dipper handle to maintain said dipper ina first tilted 1 603 573 10 /1926 Baker position; release means forunlocking said locking means 1710564 4/1929 Archil'jold 214 146 to allowsaid dipper to move to a second position when 5 2303852 12/1942 Linn Xsaid locking means is unlocked by said releaes means; and ram means onsaid dipper handle actuated by re- FOREIGN PATENTS traction of saiddipper handle to lock said locking means 444,728 5/1927 G in response toram means actuation and to return said dipper to said first position. 10HUGO O. SCHULZ, Primary Examiner.

1. IN AN EXCAVATOR HAVING A BOOM, A SADDLE BLOCK PIVOTALLY MOUNTED ONSAID BOOM, A DIPPER HANDLE SLIDEABLY CARRIED BY SAID SADDLE BLOCK, MEANSFOR RETRACTING AND THRUSTING SAID DIPPER HANDLE, AND A DIPPER PIVOTALLYMOUNTED ON SAID DIPPER HANDLE, THE COMBINATION OF: HOIST MEANS CONNECTEDTO THE DIPPER AT A POINT FORWARDLY SPACED FROM THE DIPPER PIVOT FORRAISING AND LOWERING THE DIPPER AND DIPPER HANDLE AND FOR TILTING THEDIPPER IN AN UPWARD DIRECTION ABOUT THE DIPPER PIVOT WHEN SAID DIPPER ISFREE TO TILT ABOUT ITS PIVOT; AND FLUID PRESSURE MEANS, INCLUDING ACYLINDER AND A RETRACTIBLE PISTON, CONNECTED TO SAID DIPPER HANDLE ANDSAID DIPPER, A FLUID PRESSURE CIRCUIT FOR MAINTAINING FLUID PRESSURE IN